As is known, a disc brake is provided with a bell for the connection of a wheel to the hub, and with a braking band which is mounted on the bell and is extended around it. The braking band cooperates with a brake caliper which acts by friction against braking surfaces of the braking band. As is also known, a disc braking system of “drum-in-hat” type comprises an auxiliary (parking and/or emergency) brake, usually of drum type, accommodated within the bell of the disc brake. The auxiliary brake comprises a support plate which supports the brake shoes of the drum brake and is integral with the vehicle. The brake shoes are placed within the bell and, when the auxiliary brake is actuated, they act against an inner surface of the bell in order to exert a braking force by friction.
For example, U.S. Pat. No. 6,637,553 illustrates a disc braking system of “drum-in-hat” type provided with a disc service brake and a parking and emergency drum brake accommodated within the rotor that bears the disc of the disc brake. The parking and emergency drum brake comprises a support plate which supports the brake shoes of the drum brake and also arms which bear the caliper of the disc brake.